German authorities say they have destroyed a letter addressed to the country's president that was suspected of containing explosives.

A spokesman for President Joachim Gauck's office said the letter was found during routine checks on mail late Friday morning. Experts then decided to carry out a controlled detonation of the letter in the park outside the president's Bellevue palace in downtown Berlin.

It was not immediately clear whether the letter actually contained any explosives. Germany's Federal Criminal Police Office, which was responsible for the operation, declined immediate comment.

The spokesman said there was no danger to Gauck, Germany's largely ceremonial head of state, who was not on the premises at the time. He spoke on condition of anonymity in line with department rules.